Use composite action instead of Docker action

[rhysd]

Composite action was introduced recently. It is better than the current Docker action.

• It is faster. No overhead to build and run Docker image
• It is easier to maintain. It is a single manifest file action.yml containing a small workflow steps

[paescuj]

You might be interested in this: https://full-stack.blend.com/how-we-write-github-actions-in-go.html

[rhysd]

Thanks for the information. But I think a simple composite action is better for maintenance in this case.